GOP Co-Author of Force-in-Syria Resolution Turns on Obama

President Barack Obama talks with Sen. Bob Corker during a round of golf at the Andrews Air Force Base course in May. (AP Photo/Pablo Martinez Monsivais)

(CNSNews.com) - Sen. Bob Corker (R-Tenn.), who backed President Obama's call for a military strike on Syria, expressed frustration Wednesday about the way President Obama has "muddled" his case.

"He is a diminished figure here on Capitol Hill. I can assure you of that," Corker told CNN on Wednesday.

As ranking member of the Senate Foreign Relations Committee, Corker helped draft a use-of-force authorization for a limited strike against the Assad regime in Syria. "This is one of the most serious matters that comes before the Congress," Corker said on Sept. 3, "so as we proceed to a potentially defining vote next week, the president and his administration must continue to vigorously make their case to the American people.”

But in his address to the nation Tuesday night, President Obama said he had asked Congress to postpone a vote on the use of force so he can pursue a diplomatic proposal forged by Russia.

"I really do think they hurt our credibility around the world, just in the muddled way that they have dealt with this Syrian issue," Corker told CNN on Wednesday. "It is just a complete muddlement, if you will. And I don't know, the president just seems to be very uncomfortable being commander-in-chief of this nation."

Corker said most of the Republicans who met with President Obama at lunch on Tuesday "would have believed" that he was going to make a "strategic case" for U.S. intervention in Syria in his speech to the nation.

But, "I heard no word -- not one word of it," Corker fumed. Although Obama is "a very confident person" and "very good in an interpersonal setting," he "just cannot follow through," Corker said. "He cannot speak to the nation as a commander-in-chief. He cannot speak to the world as a commander-in-chief. He just cannot do it. And I don't know what it is."

Asked if Obama has "hurt his credibility" with Corker -- who has worked with the administration on various domestic issues and has also golfed with the president -- Corker said, "Oh, there's no question. I probably shouldn't be saying everything I am saying right now. But I guess it was a result of last night, my temperature level is up slightly today. He is diminished figure here on Capitol Hill. I can assure you of that."

Corker has expressed "healthy skepticism" that Russia's diplomatic efforts will change anything in Syria. Russia, seizing on a remark made by Secretary of State John Kerry, has proposed that Syria give up its chemical weapons.

In a statement, Corker took the administration's line that the Russian proposal "would never have been floated if the Senate Foreign Relations Committee had not approved the authorization for the use of force last week."

In his speech Tuesday night, Obama said it was partly because of the "credible threat of U.S. military action" that Russia is pressing Syria to give up its chemical arsenal.

Corker backs immigration reform, and he has called the conservative push to defund Obamacare "a silly effort."